Fuel tanks on board vehicles of various kinds generally have to meet sealing and permeability standards in relation to the type of use for which they are designed and the environmental requirements that they have to satisfy. At the present time, both in Europe and throughout the world, there is a substantial tightening of the requirements regarding the limitation of pollutant emissions into the atmosphere and into the environment in general.
To limit these emissions, care is taken in particular to position the accessories (ventilation lines, valves, baffles, stiffeners, etc.) inside the tank and/or the fill pipe (see in particular Application WO 2004/024487 in the name of the Applicant). However, when these components are fastened to the tank after it has been molded, it is generally necessary to make at least one opening in the tank so as to be able to introduce said components into the tank and to fasten them thereto. Hence there may be potential sealing problems near this opening.
Several years ago the Applicant therefore developed a process of initially molding a cut parison (cut into two sections) in order to be able to introduce thereinto and fasten thereto accessories during the actual molding of the tank and to thus avoid drilling openings (see Patent EP 1 110 697 in the name of the Applicant).
It is furthermore known to use intermediate parts or connectors in order to achieve this fastening. Indeed, this way of proceeding makes it possible to easily fasten, to the tank, parts based on a material different to that which forms the inner surface of the tank. In order to do this it is sufficient to choose a connector made from a material which is compatible with that of the tank and to equip it with means for attachment to said accessory (fastening tabs, part of a “quick connect” type coupling, etc.).
Thus, Application U.S. Pat. No. 6,726,967 proposes a connector comprising a body, welding petals that open out in a flower shape from this body and a coupling mechanism (attachment means) for an accessory. However, this connector has several drawbacks:
it is bulky and reduces the working height of the tank in the (frequent) case where the accessory must be located in the gas pocket over the liquid (and not be submerged)
it is relatively heavy and adversely affects the weight of the tank (and by doing so, that of the vehicle for which it is intended)
a good welding quality requires a relatively complicated design of the welding petals.